staging: bcm2835-audio: Fixed initialization of global to "false"

bcm2835-vchiq.c:
fixing ERROR: do not initialise globals to false

Instead of explicitly initializing global variable force_bulk to "false",
declared force_bulk as static variable.

Signed-off-by: Abhijit Naik <abhijitnaik27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>